In the automated packaging of semi-solid food products such as cottage cheese it is highly desirable that products be accurately measured into containers and that product waste be reduced to a mimimum during the filling process.
In the prior art for example, valves for metering such food products into containers have suffered from what is known in the art as "tailing", i.e., the retention of such food product in the outlet nozzle or spout of a dispensing valve which tends to drop out of the spout under the force of gravity or under the drawing effect of preceeding food product as it exits the dispensing spout, with the end result that different volumes of food are presented to each successive container and spillage of the food product occurs between the presentations of containers resulting in product waste and potentially unsanitary conditions since the need for cleaning of the equipment area is increased and rendered more difficult.
Past efforts to prevent tailing and waste have involved the use of complex valve motions such as a suction stroke after the dispensing stroke to draw material back into the dispensing spout and multiple piston valves with the attendant requirements of complex volume adjustments, timing and control systems and difficulty in cleaning and sanitizing the valve structures.
Thus, there is a long felt need in the art for a simple and accurate volumetric filling valve and control system for same which is fully adapted for the automated filling of containers with semi-solid food products and which, at the same time, precludes tailing, minimizes waste and can be cleaned and sanitized with a minimum of effort. Furthermore, an additional desired feature in any such valve is the ability to make rapid and accurate volumetric adjustments of such a valve without the necessity of shutting down the filling machine with which it is associated during a production run.